1. Field of the Technology
The present technology relates to a toner cartridge which is used in an image forming apparatus using an electrophotographic system, and to an image forming apparatus.
2. Description of the Related Art
An image forming apparatus which is mounted in a printer, a copy machine, or the like forms an image using a toner which is stored in a developing device in the image forming apparatus. In the field of an image forming apparatus, a toner cartridge which supplies a toner to a developing device has been hitherto known. When the toner in the developing device is consumed, the toner cartridge supplies a toner in the toner cartridge into the developing device.
For example, in Japanese Unexamined Patent Publication JP-A 2011-33836, there is disclosed a toner cartridge comprising: a toner storage container having a toner storage section which for storing a toner which is supplied to a developing device and a toner discharge section having a toner discharge port, the toner discharge section being adjacent to the toner storage section; a toner stirring member disposed in the toner storage section, the toner stirring member having a toner stirring plate for stirring a toner stored in the toner storage section and a pair of flexible stirring blades for scooping up a toner stored in the toner storage section and conveying it to the toner discharge section; and a toner discharge member disposed in the toner discharge section, for conveying a toner which has been conveyed to the toner discharge section by the toner stirring member toward the toner discharge port.
In the toner cartridge disclosed in JP-A 2011-33836, the paired stirring blades are provided at an interval of 180 degrees in a circumferential direction of a rotating shaft, and are each disposed at the front end of each toner stirring plate protruding from the rotating shaft outwardly in a radial direction of the rotating shaft so as to extend in the radial direction outwardly. Each of the stirring blades is designed to have a length long enough to make contact with an inner surface of the toner storage section in the radial direction of the rotating shaft. In this construction, as the rotating shaft is rotated, a toner attached to the inner surface of the toner storage section can be scraped off by the paired stirring blades, wherefore the amount of toner residues that have remained on an inner wall of the toner storage section without being conveyed to the toner discharge section can be minimized.
However, in the toner cartridge disclosed in JP-A 2011-33836, since the toner conveying members start to rotate simultaneously immediately after the placement of the toner cartridge, it follows that, depending on an environment in which a toner is left standing, the toner may be solidified, with the consequence that a rotating motor is brought into a locked state, thus causing a malfunction.
Furthermore, there may be a case where a driving torque produced in a rotationally driving portion of the developing device is increased to exceed a permissible value. If the torque in the driving portion is increased to exceed a permissible value, for example, in an engagement part between gears disposed at the rotating shafts of a roller, a stirring member, etc., there will arise gear tooth slippage, or equivalently a phenomenon in which gear teeth are mutually slipped with the consequence that the gears are rotated at a dash by the number of slipped gear teeth, not rotating gears while engaging gear teeth one by one. If such a tooth slippage phenomenon occurs, the developing roller will be rotated at an excessively high speed, wherefore a sufficient amount of developer cannot be fed from the developing roller to an electrostatic latent image formed on the surface of an electrophotographic photoreceptor, which results in occurrence of image defects, namely so-called image voids.